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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

NON-CATALYTIC TRANSFER HYDROGENATION IN SUPERCRITICAL CO2 FOR COAL LIQUEFACTION AND GRAPHENE EXTRACTION

Hasan, Tanvir 01 August 2015 (has links)
The paper discusses a two-step process for the simultaneous extraction of graphene quantum dots and chemicals. The two steps are sequential structure disruption by supercritical CO2 explosion followed by a low temperature (120oC), non-catalytic transfer hydrogenation in supercritical CO2. The key idea of this research is, one hydrogen atom from hydrogen transfer agent (HTA) one hydrogen atom from water is used to hydrogenate the coal. The use of supercritical CO2 enhances the rate of hydrogenation, helps in dissolution of non-polar molecules and removal from the reaction site. The coal dissolution products are polar and non-polar. A phase transfer agent (PTA) allows seamless transport of the ions and byproduct between the aqueous and organic phases. A polar modifier (PM) for CO2 has been added to aid in the dissolution and removal of the polar components. The effect of feed conditions on the liquefaction process has been investigated. The response metrics considered were the conversion of coal and the yields of various organic classes such as ketones, alkanes, alkenes, aliphatic acids, alcohols, amines, aromatics and aromatic oxygenates. Ketones were found to be the major constituent of the products. Graphene quantum dots were also extracted.

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